Its an RPG there will be a grind one way or another. you will not find an RPG anywhere where the best way to level is not going out and killing a horde of monsters. If you don't like it then RPGs are not the games for you. Its not limiting anything just making you work with others (whole point of a MMO) to level. the only thing limiting you from doing quest/exploring or whatever else you can think of is you. Don't matter how they do leveling someone will be unhappy about it. if you don't like it don't play simple as that.